Fuel injection pump



R. LORANGE FUEL INJECTION PUMP Sept. `27, 1938.

Original Filed Sept. 14, 1935 Patented Sept. 27, 1938 UNITED STATESMarzo FUEL INJECTION PUMP Rudolf Lrange, Stuttgart-Feuerbach, GermanyOriginal application September 14, 1935, Serial No. 40,598. Diirided andthis application Au;-

gust 11, 1936, Serial No.

September 20,. 1934 1 Claim.v

This is a division from application Serial Number 40,598 of September14,1935.

This invention relates to a fuel injection pump particularly for usewith compression ignition and like engines and of the kind wherein aplunger with constant stroke operates within a barrel relative to whichit is angularly displaced for regulating the effective stroke of theplunger, the regulation being obtained by the provisionv of helicaledges which co-operate for relieving thev pump pressure at any suitablepoint of the delivery stroke according to the angular position of theplunger.

The object of the invention is to obtain a pump construction wherein theinlet stream of fuel can be readily separated from the relieving streamthereof without the employment of a hollow plunger, and the inventionconsists in this respect in the provision of a solid plunger having ahelical relieving groove which is in constant communication, through asurrounding barrel, with a relief outlet in the pump casing, the inletof said casing being in communication with the pump chamber through aport controlled by the plunger, and the relieving groove of the latterbeing adapted, in known manner, to enter, sooner or later according tothe angular position of the plunger, into communication with a recess inthe pump chamber for relieving the pump pressure through the reliefoutlet.

Fig. 1 of the accompanying drawing represents a vertical section of apump constructed according to the invention, and

Fig. 2 is a vertical section of a modified form of the pump.

'Ihe pump comprises a casing B wherein a barrel L is rigidlyfitted as aguide fora solid pump plunger M. The casing B is provided with a fuelinlet A and with a relief outlet Y, and it has two internal,circumferential grooves I and I0 each forming, together with the barrelL, a passage for the fuel. 'I'he groove I communicates with the fuelinlet A and it also communicates, through a conduit I2 in the barrel Lwith a port situated in the pump chamber 4. This port is traversed bythe upper end of the plunger M and is thus controlled by the latter. Thegroove I 0 communicates, through a duct I3, with the relief outlet Y,and it also communicates, through ducts 9, with an internal,circumferential groove 8- in the barrel L. The latter groove cooperateswith the plunger M to form a passage which is in constant communicationwith a helical relieving groove 6 made in the plunger M. There is arecess 5 made in the wall forming the pump chamber l, and the 95,3991..In Germany (CL 10S-41) relieving groove. 6' cam by angularV displace--ment of the plunger M,be put intocommunicatiorr with the pump chamberthrough the recess 5 at different points of the delivery stroke of. the

plunger for relieving the pressure in the chamber 5 through the grooveand through the relief. outlet. The volume of fuel delivered bythepumpis regulatedin this manner'. As the plunger uncovers the inlet port,fuel is admitted into the pump chamber, and after the portl hasy beenclosed. by 10 the plunger during the delivery stroke. ofthe latter,fuel. will be forced. past a delivery valve D and through a deliveryport J into thev engine cylinder until the relieving passages areopened..

As the relieving groove 6 enters into communica- 15 tion with the pumpchamber, it traverses an edge 2 of the recess'` 5 which is substantiallyparallel to the edge of the groove.

In the modified. pump construction. shown in Fig. 2, an additional duct.K is' providedv through 20 which the pump chamber communicates with therelief outlet Y. This duct opens into the pump chamber through a portwhich is substantially' on a level with the. inlet port and which isopened.

and closed simultaneously with the latter. It 25 will therefore be seenthat while the. ports are opened, the pump chamber will be flushed withfuel' passing directly from. the inlet and through the chamber' into therelief outlet. This ilow of liquid, which clears the. pump chamber ofall air 30 bubbles, continues for about one-half or twothirds of thetime occupied by the complete plunger stroke, according totheconstruction of the operating cam.

The fuel is supplied in any suitable manner, for 35.

instance by means of a separate feed pump, and', it will be seen that inboth. pump constructions a continuous passage is formed through whichfuel, which is not forced through the delivery pipe, can

circulate from. and to a supply tank which. is in 40 oscillating leverI5 which bearsl by means of a 45 f cup-shaped thrust member S againstthe head I6 of the plunger. The return stroke ofthe plungerv is effectedby a spring C which engages the plunger head inside the thrust member S.

The angular displacement of the plunger for 5o regulating the effectivestroke of the pump, is 'effected through the medium of a rod D1 which isarranged at right anglesv to the plunger and slidably mounted in rigidbearings I'l for rectilinear movement. Each pump plunger of the engineis tted with an operating lever R which is suitably coupled to the rodD1, so that the rectilinear movement oi the rod will be transmitted tothe plungers and converted in the latter to a rotary movement. Y

The casting. B which encloses the barrel L is detachably connected to acasing F which encloses the operating elements.

I claim:

A fuel injection pump of the character described comprising a casinghaving a fuel inlet and a relief outlet, a barrel' mounted in saidcasing provided on the one hand with a port` which communicates withsaid fuel inlet and on the other hand with an internal circumferentialgroove which communicates with said relief outlet, a solidpump plungerfitted snugly in said barrel and adapted to control said port, saidplunger being formed with a helical relieving groove, means forreciprocating the plunger within the barrel, said means operative tomaintain the relieving groove in constant communication with the barrelgroove while moving the free end of the plunger across said port, adelivery valve closing the end of the b rrel and forming a pump chamberbetween it and the free end of the plunger, the barrel having in saidpump chamber a recess adapted, during the delivery stroke of theplunger, to be thrown into communication with the relieving groove ofthe latter for relieving the pump pressure through the relief outlet,and means for imparting to the plunger an angular displacement in orderto determine the point of the stroke at which the relief takes place,the barrel being provided with a duct which is closed by the plungersubstantially at the same time as the inlet port and which communicateswith the relief outlet for allowing free circulation of fuel through thepump chamber when the inlet port is opened.

